Delegated Authentication
CAS can act as a client (i.e. service provider or proxy) using the Pac4j library and delegate the authentication to:
- CAS servers
- SAML2 identity providers
- OAuth2 providers such as Facebook, Twitter, GitHub, Google, LinkedIn, etc
- OpenID Connect identity providers such as Google, Apple
- ADFS
Support is enabled by including the following dependency in the WAR overlay:
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<dependency>
<groupId>org.apereo.cas</groupId>
<artifactId>cas-server-support-pac4j-webflow</artifactId>
<version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-pac4j-webflow:${project.'cas.version'}"
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dependencyManagement {
imports {
mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
}
}
dependencies {
implementation "org.apereo.cas:cas-server-support-pac4j-webflow"
}
The following settings and properties are available from the CAS configuration catalog:
cas.authn.pac4j.core.groovy-provider-post-processor.location=
The location of the resource. Resources can be URLS, or files found either on the classpath or outside somewhere in the file system. In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number ofinotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256. You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.
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cas.authn.pac4j.core.groovy-redirection-strategy.location=
The location of the resource. Resources can be URLS, or files found either on the classpath or outside somewhere in the file system. In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number ofinotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256. You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.
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cas.authn.pac4j.core.discovery-selection.json.location=
The location of the resource. Resources can be URLS, or files found either on the classpath or outside somewhere in the file system. In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number ofinotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256. You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.
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cas.authn.pac4j.core.discovery-selection.selection-type=MENU
Indicate how the selection and presentation of identity providers would be controlled. Available values are as follows:
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cas.authn.pac4j.core.lazy-init=true
Whether initialization of delegated identity providers should be done eagerly typically during startup. |
cas.authn.pac4j.core.name=
The name of the authentication handler in CAS used for delegation. |
cas.authn.pac4j.core.order=
Order of the authentication handler in the chain. |
cas.authn.pac4j.core.principal-attribute-id=
The attribute to use as the principal identifier built during and upon a successful authentication attempt. |
cas.authn.pac4j.core.replicate-sessions=true
Indicates whether profiles and other session data, collected as part of pac4j flows and requests that are kept by the container session, should be replicated across the cluster using CAS and its own ticket registry. Without this option, profile data and other related pieces of information should be manually replicated via means and libraries outside of CAS. |
cas.authn.pac4j.core.typed-id-used=false
When constructing the final user profile from the delegated provider, determines if the provider id should be combined with the principal id. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
The client issuing the authentication request can be of any type (SAML, OAuth2, OpenID Connect, etc) and is allowed to submit the authentication request using any protocol that the CAS server supports and is configured to understand. This means that you may have an OAuth2 client using CAS in delegation mode to authenticate at an external SAML2 identity provider, another CAS server or Facebook and in the end of that flow receiving an OAuth2 user profile. The CAS server is able to act as a proxy, doing the protocol translation in the middle.
Register Providers
An identity provider is a server which can authenticate users (like Google, Yahoo…) instead of a CAS server. If you want to delegate the CAS authentication to Twitter for example, you have to add an OAuth client for the Twitter provider, which will be done automatically for you once provider settings are taught to CAS.
Notice that for each OAuth provider, the CAS server is considered as an OAuth client and therefore should be declared as an OAuth client at the OAuth provider. After the declaration, a key and a secret is given by the OAuth provider which has to be defined in the CAS configuration as well.
Default
Identity providers for delegated authentication can be registered with CAS using settings.
| Provider | Reference |
|---|---|
| Apple | See this guide. |
| Azure AD | See this guide. |
| CAS | See this guide. |
| DropBox | See this guide. |
| See this guide. | |
| FourSquare | See this guide. |
| Generic OpenID Connect | See this guide. |
| GitHub | See this guide. |
| See this guide. | |
| Google OpenID Connect | See this guide. |
| HiOrgServer | See this guide. |
| Keycloak | See this guide. |
| See this guide. | |
| OAuth20 | See this guide. |
| PayPal | See this guide. |
| SAML | See this guide. |
| See this guide. | |
| WindowsLive | See this guide. |
| Wordpress | See this guide. |
| Yahoo | See this guide. |
REST
Identity providers for delegated authentication can be provided to CAS using an external REST endpoint.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.pac4j.rest.url=
The endpoint URL to contact and retrieve attributes. |
cas.authn.pac4j.rest.basic-auth-password=
If REST endpoint is protected via basic authentication, specify the password for authentication. |
cas.authn.pac4j.rest.basic-auth-username=
If REST endpoint is protected via basic authentication, specify the username for authentication. |
cas.authn.pac4j.rest.cache-duration=PT8H
Control the expiration policy of the cache that holds on the results from the rest api. This settings supports the
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cas.authn.pac4j.rest.headers=
Headers, defined as a Map, to include in the request when making the REST call. Will overwrite any header that CAS is pre-defined to send and include in the request. Key in the map should be the header name and the value in the map should be the header value. |
cas.authn.pac4j.rest.method=GET
HTTP method to use when contacting the rest endpoint. Examples include |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
This allows the CAS server to reach to a remote REST endpoint whose responsibility is to produce the following payload in the response body:
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{
"callbackUrl": "https://sso.example.org/cas/login",
"properties": {
"github.id": "...",
"github.secret": "...",
"cas.loginUrl.1": "...",
"cas.protocol.1": "..."
}
}
The syntax and collection of available properties in the above
payload is controlled by the pac4j library.
The response that is returned must be accompanied by a 200 status code.
Profile Attributes
In CAS-protected applications, through service ticket validation, user information are pushed to the CAS client and therefore to the application itself.
The identifier of the user is always pushed to the CAS client. For user attributes, it involves both the configuration at the server and the way of validating service tickets.
On CAS server side, to push attributes to the CAS client, it should be configured in the expected service:
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{
"@class" : "org.apereo.cas.services.RegexRegisteredService",
"serviceId" : "sample",
"name" : "sample",
"id" : 100,
"description" : "sample",
"attributeReleasePolicy" : {
"@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
"allowedAttributes" : [ "java.util.ArrayList", [ "name", "first_name", "middle_name" ] ]
}
}
Discovery Selection
Please see this guide.
Authentication Policy
Please see this guide.
Provisioning
Please see this guide.
Post Processing
Please see this guide.
Session Replication
For the current active session, the selected identity provider, the relying party and all other relevant details for the given authentication request are tracked as session attributes inside a dedicated session store capable of replication, which is specially more relevant for clustered deployments.
The following settings and properties are available from the CAS configuration catalog:
cas.session-replication.cookie.allowed-ip-addresses-pattern=
A regular expression pattern that indicates the set of allowed IP addresses, when |
cas.session-replication.cookie.auto-configure-cookie-path=true
Decide if cookie paths should be automatically configured based on the application context path, when the cookie path is not configured. |
cas.session-replication.cookie.comment=CAS Cookie
CAS Cookie comment, describes the cookie's usage and purpose. |
cas.session-replication.cookie.domain=
Cookie domain. Specifies the domain within which this cookie should be presented. The form of the domain name is specified by RFC 2965. A domain name begins with a dot (.foo.com) and means that the cookie is visible to servers in a specified Domain Name System (DNS) zone (for example, www.foo.com, but not a.b.foo.com). By default, cookies are only returned to the server that sent them. |
cas.session-replication.cookie.http-only=true
true if this cookie contains the HttpOnly attribute. This means that the cookie should not be accessible to scripting engines, like javascript. |
cas.session-replication.cookie.max-age=-1
The maximum age of the cookie, specified in seconds. By default, |
cas.session-replication.cookie.name=
Cookie name. Constructs a cookie with a specified name and value. The name must conform to RFC 2965. That means it can contain only ASCII alphanumeric characters and cannot contain commas, semicolons, or white space or begin with a |
cas.session-replication.cookie.path=
Cookie path. Specifies a path for the cookie to which the client should return the cookie. The cookie is visible to all the pages in the directory you specify, and all the pages in that directory's subdirectories. A cookie's path must include the servlet that set the cookie, for example, /catalog, which makes the cookie visible to all directories on the server under /catalog. Consult RFC 2965 (available on the Internet) for more information on setting path names for cookies. |
cas.session-replication.cookie.pin-to-session=true
When generating cookie values, determine whether the value should be compounded and signed with the properties of the current session, such as IP address, user-agent, etc. |
cas.session-replication.cookie.same-site-policy=
If a cookie is only intended to be accessed in a first party context, the developer has the option to apply one of settings SameSite=None, to designate cookies for cross-site access. When the SameSite=None attribute is present, an additional Secure attribute is used so cross-site cookies can only be accessed over HTTPS connections. Accepted values are:
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cas.session-replication.cookie.secure=true
True if sending this cookie should be restricted to a secure protocol, or false if the it can be sent using any protocol. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
Webflow
Certain aspects of the webflow configuration for delegated authentication can be controlled via the following settings:
The following settings and properties are available from the CAS configuration catalog:
cas.authn.pac4j.webflow.enabled=true
Whether webflow auto-configuration should be enabled. |
cas.authn.pac4j.webflow.order=0
The order in which the webflow is configured. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
Troubleshooting
To enable additional logging, configure the log4j configuration file to add the following levels:
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...
<Logger name="org.pac4j" level="debug" additivity="false">
<AppenderRef ref="console"/>
<AppenderRef ref="file"/>
</Logger>
...